The present invention relates to a tool or tool holder with which at least one sensor operating in a contactless manner is associated functionally and spatially whose measurement signals are input to a signal processing unit for evaluation.
A known tool holder of this type (German Patent Application DE 42 38 338 A1) is provided with an observation device for a tool in order to determine the extent of wear and/or to detect breakage of a tool in a tool holder of an operating machine. The observation device has a stationary displacement sensor that can detect a dislocation or displacement. The displacement sensor is arranged spatially fixed in the supporting housing of the tool spindle. A reference surface is provided on the rotating tool spindle spaced from it. The spacing of the reference surface from the displacement sensor depends on the force occurring during operation with the tool. If this spacing changes during operation, e.g. due to a tool breaking, it is detected by the displacement sensor in a contactless manner and is fed to an associated signal processing unit in the form of a suitable signal. The stationary displacement sensor requires an energy supply for signal production. Battery supplied sensors with VHF signal transmission or with signal transmission on an infrared basis are known. These observation devices are expensive, troublesome and already have considerable disadvantages because of the required current supply for the sensors, especially those supplied with current from batteries, because of technical considerations for the batteries.